For a given $op_name (for example, 'cop_label', 'sv_flags', etc...) you get an array ref containing the bytecode number of the op, a reference to the subroutine used to 'PUT', and the name of the method used to 'GET'.

Certain SV types are considered 'special'. They're represented by B::SPECIAL and are refered to by a number from the specialsv_list. This array maps that number back to the name of the SV (like 'Nullsv' or '&PL_sv_undef').